Explanation:

- Cementum:

- Correct Answer: Covers the root of the tooth.

- Hard, calcified material.

- Anchors the tooth to the jawbone with periodontal ligaments.

- Forms a protective layer over the root.

- Pulp:

- Soft, innermost part of the tooth.

- Contains nerves and blood vessels.

- Provides nutrients and sensory function.

- Dentin:

- Beneath the enamel and cementum.

- Hard tissue but softer than enamel.

- Makes up the bulk of the tooth's structure.

- Enamel:

- Hard outer covering of the crown, not the root.

- Protects teeth from decay.

- Hardest substance in the human body.